EURURO Vol. 73 No. 1

95 148

1. Introduction
Renal transplantation is the gold standard renal replace-
ment therapy in end-stage renal disease (ESRD) owing to its
superior survival and quality of life compared with other
replacement therapies .
The standard procedure for transplantation candidates
includes systematic screening for the presence of any
active/latent cancer or a history of cancer . In transplan-
tation candidates with a previous history of urological
cancer, it can be challenging to decide if patients are
suitable for transplantation and if so how long the waiting
period prior to transplantation should be. So far, the clinical
decision has been mainly based on the Cincinnati Registry,
which essentially considers the type of tumour and the
time between its treatment and kidney transplantation
. The waiting period varies from less than 2 yr to at least
5 yr according to the Registry. However, the Cincinnati
Registry has several deficiencies: (1) the treatment and the
staging of the disease are not defined, (2) the epidemiology
of tumours, (3) the diagnostic and therapeutic procedures/
tests have changed, and (4) the prognostic tools have
improved.
The objective of this systematic review was to appraise
all available evidence on the risk of cancer recurrence in
ESRD patients who underwent transplantation after having
been successfully treated for a urological cancer. The
primary objectives were to determine in patients with
chronic kidney disease (CKD) 4/5 and a history of urological
cancer, the risk of tumour recurrence after transplantation
compared with renal replacement therapy (peritoneal and
haemodialysis). The secondary objectives were to report on
the overall and cancer-specific survival of transplanted and
nontransplanted patients with a history of malignancy and
to determine for each urological cancer the minimum
tumour-free waiting period prior to transplantation.
2. Evidence acquisition
2.1. Data sources and searches
The systematic review was performed according to the
Preferred Reporting Items for Systematic Reviews and Meta-
analyses The systematic review protocol was registered
with PROSPERO
). Studies (January
1, 1995, to March 1, 2016) were identified by highly
sensitive searches of electronic databases (Medline,
Embase, Cochrane library databases). The initial literature
search was performed in February 2016 and an updated
search performed in March 2017. The search was compli-
mented by additional sources including the reference lists
of included studies. The search strategy is described in
detail in Supplementary data.
2.2. Study selection
There was no restriction on types of study design. All
randomised control studies, nonrandomised comparative
studies, and noncomparative studies (single-arm cohort
studies, case reports), and meta-analyses published in the
English language were included.
2.3. Types of participants
The study populationwas adults ( 18 yr) with CKD 4/5 and
previous urological cancer under renal replacement therapy
or who subsequently underwent renal transplantation.
2.4. Data collection and data extraction
Following deduplication of abstracts, two reviewers (R.B. and
V.H.) screened all abstracts and full-text articles indepen-
dently. Disagreement was resolved by a third party (M.B.).
References cited in all full-text articles were also assessed for
additional relevant articles. A standardised data-extraction
form was developed a priori to collect information on study
design, patient characteristics (sex and age, type of urological
cancer, baseline risk of tumour recurrence [based on stage,
grade, histology, or risk stratification using nomograms or
risk groups]), interventions (duration of dialysis before
cancer treatment, type and duration of immunosuppressive
regimens, duration of tumour-free period prior to transplan-
tation), and outcome measures (cancer recurrence, cancer-
specific, and overall survival).
2.5. Risk of bias assessment
Two reviewers (R.B. and V.H.) independently assessed the
risk of bias (RoB) of each included study any discrepancies
were revolved by a third reviewer (M.B.). The Cochrane RoB
tool was used for RoB assessment. For nonrandomised
studies, the tool was modified to include an additional
domain to assess the risk of confounding bias. A list of five
important potential confounderswas developed a priori with
clinical content experts (European Association of Urology
Renal Transplantation Guidelines Panel) . The confoun-
ders included were: (1) type of urological cancer, (2) baseline
transplantation could be reduced. Except in the particular situation of aristolochic acid
nephropathy, more studies are needed to standardise the waiting period after UC owing to
the paucity of data.
Patient summary: Renal transplantation does not appear to increase the risk of recurrence
of renal carcinoma or the recurrence of low-risk prostate cancer compared with dialysis.
More reliable evidence is required to recommend a standard waiting period especially for
urothelial and testicular carcinomas.
© 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.
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